Pointing mechanism is widely used in aerospace field,and its pointing accuracy and stability have high requirements.The pointing mechanism will be affected by external interference when it works.In order to eliminate ...Pointing mechanism is widely used in aerospace field,and its pointing accuracy and stability have high requirements.The pointing mechanism will be affected by external interference when it works.In order to eliminate the impact of interference forces on the output accuracy of the mechanism,firstly,this paper proposes a design method for highprecision pointing mechanisms based on interference separation,aiming at the high-precision pointing requirements of pointing mechanisms.Based on the screw theory,a synthesis method for inner compensation mechanisms has been proposed.And a new type of double-layer parallel mechanism has been designed to compensate for interference forces.Then,the kinematics and dynamics of the mechanism are carried out.An evaluation index for compensating external interference forces is proposed.The interference compensation analysis is conducted for the pointing mechanism.The correctness of the proposed interference force compensation coefficient is verified.Finally,in order to find the optimal solution for the workspace and interference force compensation coefficient of the pointing mechanism,multi-objective optimization design of the structural parameters of the mechanism was carried out based on the particle swarm optimization algorithm.This provides a theoretical basis for the prototype design of the subsequent double-layer parallel mechanism.This double-layer parallel mechanism combines the advantages of large load-bearing capacity,large workspace,and high output accuracy.It can be better applied in the aerospace field where high-precision pointing and force interference compensation are integrated.展开更多
Various types of interference signals limit the practical application of transform domain communication systems(TDCSs)in the severe electromagnetic field,an orthogonal basis learning method of transformation analysis(...Various types of interference signals limit the practical application of transform domain communication systems(TDCSs)in the severe electromagnetic field,an orthogonal basis learning method of transformation analysis(OBL-TA)is proposed to effectively address the problem of obtaining an optimal transform domain based on sparse representation.Then,the sparse availability is utilized to obtain the optimal transformation analysis by the iterative methods,which yields the sparse representation for transform domain(SRTD)in unrestricted form.In addition,the iterative version of SRTD(I-SRTD)in unrestricted form is obtained by decomposing the SRTD problem into three sub-problems and each sub-problem is iteratively solved by learning the best orthogonal basis.Furthermore,orthogonal basis learning via cost function minimization process is conducted by stochastic descent,which is assured to converge to a local minimum at least.Finally,the optimal transformation analysis is developed by the effectiveness of different transform domains according to the accuracy of the sparse representation and an optimal transformation analysis separately(OPTAS)is applied to the synthesized signal forms with conic alternatives,dualization,and smoothing.Simulation results demonstrate that the superiorities of the proposed methods achieve the optimal recovery and separation more rapidly and accurately than conventional methods.展开更多
基金Supported by the National Natural Science Foundation of China(52275032)the Natural Science Foundation of Hebei Province(E2022203077)+1 种基金the Hebei Provincial Science and Technology Plan(22371801D)the Hebei Provincial Science and Technology Research and Development Program-Central Guidance for Local Science and Technology Development Fund(246Z1818G).
文摘Pointing mechanism is widely used in aerospace field,and its pointing accuracy and stability have high requirements.The pointing mechanism will be affected by external interference when it works.In order to eliminate the impact of interference forces on the output accuracy of the mechanism,firstly,this paper proposes a design method for highprecision pointing mechanisms based on interference separation,aiming at the high-precision pointing requirements of pointing mechanisms.Based on the screw theory,a synthesis method for inner compensation mechanisms has been proposed.And a new type of double-layer parallel mechanism has been designed to compensate for interference forces.Then,the kinematics and dynamics of the mechanism are carried out.An evaluation index for compensating external interference forces is proposed.The interference compensation analysis is conducted for the pointing mechanism.The correctness of the proposed interference force compensation coefficient is verified.Finally,in order to find the optimal solution for the workspace and interference force compensation coefficient of the pointing mechanism,multi-objective optimization design of the structural parameters of the mechanism was carried out based on the particle swarm optimization algorithm.This provides a theoretical basis for the prototype design of the subsequent double-layer parallel mechanism.This double-layer parallel mechanism combines the advantages of large load-bearing capacity,large workspace,and high output accuracy.It can be better applied in the aerospace field where high-precision pointing and force interference compensation are integrated.
基金supported by the University Cooperation Project Foundation of the Key Laboratory for Aerospace Information Technology(KX162600022).
文摘Various types of interference signals limit the practical application of transform domain communication systems(TDCSs)in the severe electromagnetic field,an orthogonal basis learning method of transformation analysis(OBL-TA)is proposed to effectively address the problem of obtaining an optimal transform domain based on sparse representation.Then,the sparse availability is utilized to obtain the optimal transformation analysis by the iterative methods,which yields the sparse representation for transform domain(SRTD)in unrestricted form.In addition,the iterative version of SRTD(I-SRTD)in unrestricted form is obtained by decomposing the SRTD problem into three sub-problems and each sub-problem is iteratively solved by learning the best orthogonal basis.Furthermore,orthogonal basis learning via cost function minimization process is conducted by stochastic descent,which is assured to converge to a local minimum at least.Finally,the optimal transformation analysis is developed by the effectiveness of different transform domains according to the accuracy of the sparse representation and an optimal transformation analysis separately(OPTAS)is applied to the synthesized signal forms with conic alternatives,dualization,and smoothing.Simulation results demonstrate that the superiorities of the proposed methods achieve the optimal recovery and separation more rapidly and accurately than conventional methods.
